This invention relates to a method for producing a threaded projection on a plate-shaped workpiece, and in particular on a sheet metal workpiece, the threaded projection extends at an angle relative to the principal plane of the workpiece, and is produced in the form of a lug, one end of which connects to and extends on at least one side from the junction with the body of the workpiece and which is provided with a threaded contour.
The invention further relates to a machine system serving to implement said method and encompassing a cutting device for the relief cutting of lugs on workpieces, a thread cutting device, and a bending device. By means of the relief cutting device for cutting lugs on the workpiece, such lugs can be cut clear so as to leave a connection at one end to the body of the workpiece. The thread cutting device can produce a thread on at least one side of the lug that extends from the remaining workpiece, and that the bending device enables at least one section of the lug can be bent at a permanent angle relative to the principal plane of the workpiece.
Finally, the invention relates to a thread cutting device within a machine system of the type referred to above.
U.S. Pat. No. 2,983,179 describes a prior art system in the general category described above. In the case of that prior art system, the first step is to produce in a sheet metal workpiece two parallel slots extending from the edge of the workpiece in the direction of the center of the workpiece. The metal tongue thus cut free is subsequently folded up. This results in a folded leg with two closely neighboring sides that extend at an angle perpendicular to the principal plane of the workpiece being processed. Finally, a corresponding die stamps a threaded contour onto the forward ends of the folded legs. The threaded contours on the mutually opposite forward ends of the folded legs constitute segments of a screw thread that will accept a threaded nut.
It is the objective of this invention to improve on this earlier methodology for producing threaded lugs and to introduce devices that permit the implementation of such procedurally improved methodology.